[SPARK-9536] [SPARK-9537] [SPARK-9538] [ML] [PYSPARK] ml.classification...

[SPARK-9536] [SPARK-9537] [SPARK-9538] [ML] [PYSPARK] ml.classification support raw and probability prediction for PySpark

Make the following ml.classification class support raw and probability prediction for PySpark:
```scala
NaiveBayesModel
DecisionTreeClassifierModel
LogisticRegressionModel
```

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #7866 from yanboliang/spark-9536-9537 and squashes the following commits:

2934dab [Yanbo Liang] ml.NaiveBayes, ml.DecisionTreeClassifier and ml.LogisticRegression support probability prediction